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Vehicle: |
BMW |
Disclaimer: This information is
provided as a reference only. The information provided
on this site is provided "as is" without warranty of any kind, either express or implied,
including, but not limited to, the implied warranties of merchantability,
fitness for a particular purpose, or non-infringement. No liability is assumed
for use or interpretation of information contained in these documents on this
web site. Any decisions or actions based on the data or information contained
in this site are the responsibility of the individual user. Should you decide that you want to change your brake pads on your own, be sure that your car is properly jacked and supported. Wear safety goggles or glasses at all times. |
Introduction:
Changing the brake pads is fairly easy process. A novice you can expect to spend about 1.5 – 2.0 hours to change pads on all four brakes.
Tools:
The following tools will be needed to successfully change your brake pads.
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Item |
Description |
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3/8" socket wrench |
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7mm Hex Bit Socket (short) |
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3 pound hammer |
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18" of insulated solid wire or length from a coat hanger |
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3/8" Torque wrench (optional) |
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C clamp |
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2 Large flat head screwdrivers |
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New brake pads |
Supplies:
It is helpful to have the following supplies on hand when changing brake pads:
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Item |
Description |
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Brake cleaner |
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Shop cloth |
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Putty knife |
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Plastilube (BMW 81 22 9 407 103) or Wurth DGQ 2200 |
Spares:
If you change your pads frequently and/or you participate in track events it is wise to keep these supplies on hand. They are either easy to brake, loose, or will wear out. You do not want to be without these supplies, especially, if you are away from home.
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Item |
Description |
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Sensor cable. It is easy to break to separate the cable when trying to remove the sensor. This is not critical but if your pads wear low your sensor will not warn you if you leave these disconnected. |
Steps:
The following step by step instructions will lead you through changed your brake pads on an E36 M3. These instructions assume that you have properly and safely jacked up your car, removed the wheel and the brakes are cool. Pictures show different calipers from step to step (front/rear) but the actions are identical.
| Item | Step | Description |
| 1 | Remove brake clips |
Insert the flat head
screwdriver under the clip and the other between the hub and the top of top
of the clip. Pry the screwdriver between the hub and the top of the clip towards the brake caliper. Pry until you see the catches clip move to the outside of the holes in the caliper. Pry the other screwdriver towards the hub. Until the clip springs free. You may have to adjust your prying on both screw drivers until the clip comes free. Be careful and make sure that your face and hands are clear since the clip will pop free. Once the clip is removed you will want to set it aside so it does not get stepped on or lost. |
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2 |
Remove hex caps |
There are two little
plastic caps about the diameter of a dime behind the caliper. Since you can not
see these easily you will have to feel around for them. Use your thumbnail to catch the edge and push them out gently. You will push away from the caliper towards the wheel hub. I work it out about ¼"and then pinch with my thumb and forefinger to work it out. Avoid using a screwdriver to pry it out. It comes out fairly easily and you do not want to mare the plastic. Set them aside with your brake clips so they do not get damaged or lost. |
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3 |
Disconnect sensor |
There are only two brake
wear sensors on the car. One is on the front driver side and the other is on
the rear passenger side. It is a small green insulated wire that runs from a
connection mounted in the wheel hub and leads to the edge of one of the brake
pads. These are tricky to
remove because the connector on the pad is ceramic. You do not want to break
this since it will trigger the brake warning light in your car. Gently using the flat end
of your screw driver push the sensor to the outside. Once it is about half
way off use your fingers to pinch and gently pull while you continue to apply
pressure with the screw driver. You do not want to pull the wire out of the
sensor. If you are changing to race pads or intend to change the pads well before they are worn you do not have to reattach the sensor. On a quick change for a race day there is no need to risk damage to the sensor by repeated removal and installation. You do not want to leave the wire hanging free if you are not going to reattach it. You can double it back through the clip on the shock tower. You can also use electrical tape to secure the wire to the shock mount. In the rear, you can use the additional clip on the lower control arm to double back the sensor. |
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4 |
Free hex bolts |
Using your 3/8"socket
wrench with the hex bit socket insert the bit into the hole where you removed
the hex caps. Be sure that your socket is set for a counter clockwise catch.
Turn the wrench until bit inserts into the hex bolt. You have to do this by
feel since you can not see what the recessed hex bolt. To loosen the hex bolt
hold the socket wrench in place near the head of the wrench and tap the
handle of the wrench with the hammer to force it in a clockwise direction. The removal of the nut is in reverse because your angle of attack is from behind. |
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5 |
Free caliper |
Removing the caliper can
be difficult especially if the the brake pads are old and worn. The
piston in the caliper will keep the pads firmly against the rotor even when
the brakes are not applied. You will need to loosen the grip of the
piston to facilitate the removal of the caliper. You will use a flat
head screw driver to push the piston back into the caliper. Through the
opening in the caliper you will see the top of the brake pad and the slot in
it for the wear sensor. You can slide a flat head screw driver
into the sensor slot between the brake pad backing and the
piston. Gently pull the screw driver towards you pressing the
piston back into the caliper. Make sure that the flat head screw driver
is in contact with the piston and not the rubber flange. You do not
need to insert the screw driver beyond the depth of sensor notch. You will find it easier
to remove the caliper if you take care to properly recess the piston. Use a screw driver to pry the caliper away from the rotor. The caliper will be hard to remove if the pads have been on for a wile since they have tightly conformed to the rotor. Don't be surprised if some of the inside edge of the brake pads chip away as you try to remove the caliper. If the using the screw
driver method does not free the caliper you may need to use the 3lb hammer to
help loosen the grip of the pads on the rotor. Tap the caliper with the
hammer handle in one hand while holding the caliper with your other hand to
catch it should it fall free from the rotor. The outside brake pad is not attached to the caliper. As you loosen the caliper use your other hand to hold the outside pad before you pull the caliper free. |
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6 |
Hang caliper |
Use the length of wire and hook one end through the caliper and wrap the other through the spring. If the wire is soft be sure to loop it at the ends so it does not loosen and cause the caliper to fall free. Be sure that the caliper hangs without tension on the brake line. |
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7 |
Remove pads |
If the outside pad did not fall free when removing the caliper remove it now. The inside caliper is held in place by a clip on the pad. You will have to pull the pad forward from the caliper piston to free the pad.
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8 |
Clean pistons |
Spray brake cleaner
inside of the caliper and wipe with a dry shop cloth. If any anti squeak has
been used you may have to scrape it off using a putty knife. You wan to make sure that you have a clean caliper for the new pads. |
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9 |
Recess piston |
If your old pads are worn the caliper piston will be extended. This means the new pad will not sit flush against the caliper. If the new pad is not flush you will have a hard time repositioning the caliper. To recess the piston you will press it back using the C Clamp. Use an old pad between the clamp and the piston opening to prevent damage to the piston. |
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10 |
Prep new pads |
This step is optional. Apply the anti squeak compound to the outside of the intended brake pad. Do NOT apply it to the brake surface. |
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11 |
Install new pads |
The front inside pad has a clip that inserts into the caliper piston to hold it in place. Insert the outside pad into the caliper make sure that the brake surfaces are facing in and that the pads are not upside down. |
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12 |
Position caliper |
Push the caliper towards the wheel hub until it is in position. The hex pins should line up over the holes in the caliper bracket. |
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13 |
Tighten hex bolts |
Use your
socket wrench with the hex bit turn counter clockwise since your angle of
attack is from the rear. You will want to tighten your hex bolts to 30NM or 22 ft lb. If you do not have a 3/8" torque wrench then hold the socket wrench at the hub and give the handle a few taps with the 3lb hammer until the hex bolt is tight. You do not want to pound it and over tighten the bolt. |
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14 |
Insert hex caps |
Insert the cap into the hex bolt opening and push with your fingers until it is flush. It is very important to install these to keep the hex bolt free from road grime and corrosion. |
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15 |
Intall clip |
Reinstall the clip by resting the flexible tabs on the outer edge of the bracket then press from the hub outwards until the two inner tabs drop back into the two retaining holes. |
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16 |
Installation complete |
The installation of the new pads is complete
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17 |
Pump brake pedal |
IMPORTANT: Before you drive the car make sure that you pump the brake a few times. This will help set the pads and restore pressure to the caliper pistons. If you do not do this you will find that the brakes will not grab and you will slide out of your driveway. |
